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Overview of Computer Graphics
This document provides an overview of computer graphics. It discusses the definition of computer graphics, goals of computer graphics, applications of computer graphics, graphics systems including images, hardware and software. It also describes two dimensional and three dimensional images, color models, input devices like keyboards and scanners, the computation stage involving transformations and rasterization, output devices like displays, and basics of animation.
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Introduction to the Computer Graphics presentation by the Department of Computer Science & Engineering at Hamdard University, Bangladesh.
Defining computer graphics as tech for design and communication; explains goals like effective visual communication and using diverse type styles.
Lists various applications of computer graphics in fields like biology, design, education, gaming, and visualization.
Gives an overview of graphics systems, including images, hardware (input/output systems), and software like OpenGL.
Explains two-dimensional images using X and Y axes and introduces three-dimensional images adding the Z axis.
Introduces RGB color model used in graphics, along with mentions of other color spaces like HSV and CMY.
Describes the hardware pipeline for graphics, focusing on input, computation, output, and introduces bitmap and vector display systems.
Defines object representation using the VERTEX method and explains the importance of connectivity in object representation.
Lists various input devices for graphics applications, including locator devices, keyboards, and cameras.
Explains the computation stage in graphics which involves transformations, rasterization, and memory allocation.
Discusses the frame buffer's role in memory to store rendered images, including details on pixel count and resolution.
Identifies image quality issues such as resolution, color, refresh rate, and viewing angle sensitivity.
Defines pixels and their importance in screen resolution, detailing CRT and LCD technologies in displays.
Details on Cathode Ray Tube technology, including methods of color display and characteristics.
Describes Liquid Crystal Displays, their operation, and advantages like low power consumption and flat design.
Introduction to projection displays using CRT or LCD screens to generate images for larger viewing.
Discusses special purpose software in graphics like Excel and AutoCAD, including programming APIs.
Defines computer animation and its role in digital display technology simulating movement on screens.
Explains the technique of displaying animation through sequences of images to create a smooth flow.
Overview of Computer Graphics
- 1. Computer Graphics Department ofComputer Science & Engineering Hamdard University Bangladesh Prepared By
- 2. The definition ofcomputer graphics is the technology that deals with designs and pictures on computers. Computer graphics 2
- 3. • Recognize howa visual image can be an effective means of communication • Distinguish and interpret various types of typography. • Utilize a broad range of type styles in combination with visual images. • Use a computer to create and manipulate images and text for use in various print and digital mediums. Goals of Computer Graphics 3
- 4. Applications of ComputerGraphics o Computational biology o Computational physics o Computer-aided design o Digital art o Education o Graphic design o Information visualization o Scientific visualization o Special Effects for cinema o Video Games o Web design o Design 4
- 5. Overview of GraphicsSystems • Images • Hardware – Input Systems – Output Systems • Software – OpenGL 5
- 6. Two Dimensional Images •Images (at least the ones in this class) are two dimensional shapes. • The two axes we will label as X (horizontal), and Y (vertical). X Axis Y Axis (0,0) +X +Y 6
- 7. Three Dimensional Images •The three axis: X (horizontal), Y (vertical) and Z (middle). 7
- 8. Color Model RGB Colorcube (what we use in computer graphics) Other color spaces include HSV, CMY, and YIQ 8
- 9. Hardware Pipeline Input OutputComputation Wewant to draw a rectangle, how do we describe it to a computer? Model (n) - object description that a computer understands. 9
- 10. Record every position Bitmap- a rectangular array of bits mapped one-to-one with pixels. 10
- 11. Position relative Vector displaysystem - graphical output system that was based on strokes (as opposed to pixels). Also known as: random, calligraphic, or stroke displays. 11
- 12. Representing Objects • Mostcommon method is the VERTEX method. Define the object as a set of points with connectivity information. • Why is connectivity important? Connectivity - information that defines which vertices are connected to which other vertices via edges. Edge - connects two vertices 12
- 13. Input Devices • LocatorDevices • Keyboard • Scanner – Images – Laser • Cameras 13
- 14. Locator Devices When queried,locator devices return a position and/or orientation. • Tablet • Joystick • Virtual Reality Trackers – Data Gloves – Digitizers 14
- 15. Keyboard • Text input –List boxes, GUI – CAD – Modeling • Hard coded – Vertex locations are inserted into code 15
- 16. Computation Stage • Nowthat we have a model of what we want to draw, what goes on inside the computer to generate the output? Input OutputComputation Computation Transformations Rasterization 16
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- 18. Store process inmemory We would like to allocate memory to hold the results of the computation stage. 18
- 19. Frame buffer Frame buffer– The picture definition is stored in a memory is called refresh or frame buffer. Pixel - one element of the framebuffer 19
- 20. Basic architecture ofraster graphics of frame buffer 20
- 21. Frame buffer inMemory • If we want a frame buffer of 640 pixels by 480 pixels, we should allocate: Frame buffer = 640*480 bits =307200 bits =38400 bytes =38.4 kilobytes 21
- 22. Output • Hardcopy • Display –Vector or random scan – Raster Scan Input OutputComputation 22
- 23. Image Quality Issues •Screen resolution • Color • Blank space between the pixels • Intentional image degradation • Brightness • Contrast • Refresh rate • Sensitivity of display to viewing angle 23
- 24. Pixels Pixel - Thepixel (a word invented from "picture element") is the basic unit of programmable color on a computer display or in a computer image. CRT - Color triad (RGB phosphor dots) LCD - Single color element • Screen Resolution - measure of number of pixels on a screen (m by n) m - Horizontal screen resolution n - Vertical screen resolution 24
- 25. Raster Displays • CathodeRay Tubes (CRTs), most “tube” monitors. Very common, but big. • Liquid Crystal Displays (LCDs), there are two types transmissive (laptops, new flat panel monitors) and reflective (wrist watches). 25
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- 27. CRT color monitor 1.Beam Penetration Method (Red & Green) 2. Shadow Mask Method (RGB) 27
- 28. CRTs • Strong electricalfields and high voltage • Very good resolution • Heavy, not flat 28
- 29. Liquid Crystal Displays(LCDs) • Also divided into pixels, but without an electron gun firing at a screen, LCDs have cells that either allow light to flow through, or block it. 29
- 30. Advantages of LCDs •Flat • Lightweight • Low power consumption 30
- 31. Projection Displays • Usebright CRT or LCD screens to generate an image which is sent through an optical system to focus on a (usually) large screen. 31
- 32. Basic Projector Designs ReflectiveProjection System Transmittive Projection System 32
- 33. Graphics Software • Specialpurpose software – Excel – AutoCAD – Medical Visualization • Programming API 33
- 34. Computer animation isa general term for a kind of visual digital display technology that simulates moving objects on-screen. Computer animation 34
- 35. Displaying animation sequences •Movies work by fooling our eyes • A sequence of static images presented in a quick succession appears as continuous flow 35
- 36. Displaying animation sequences •To achieve smooth animation, a sequence of images (frames) have to be presented on a screen with the speed of at least 30 per second • Animations frames can be – pre-computed in advance and pre-loaded in memory – computed in real time (e.g. movement of the cursor) 36